Problem: Khan.scratchpad.disable(); Gabriela sells magazine subscriptions and earns $$9$ for every new subscriber she signs up. Gabriela also earns a $$21$ weekly bonus regardless of how many magazine subscriptions she sells. If Gabriela wants to earn at least $$87$ this week, what is the minimum number of subscriptions she needs to sell?
Answer: To solve this, let's set up an expression to show how much money Gabriela will make. Amount earned this week $=$ $ $ Subscriptions sold $\times$ Price per subscription $+$ Weekly bonus Since Gabriela wants to make at least $$87$ this week, we can turn this into an inequality. Amount earned this week $\geq $87$ Subscriptions sold $\times$ Price per subscription $+$ Weekly bonus $\geq $87$ We are solving for the number of subscriptions sold, so let subscriptions sold be represented by the variable $x$ We can now plug in: $x \cdot $9 + $21 \geq $87$ $ x \cdot $9 \geq $87 - $21 $ $ x \cdot $9 \geq $66 $ $x \geq \dfrac{66}{9} \approx 7.33$ Since Gabriela cannot sell parts of subscriptions, we round $7.33$ up to $8$ Gabriela must sell at least 8 subscriptions this week.